Metabotypes in the Urinary Excretion of Flavan-3-ol Metabolites: "Metanols"

Summary

Flavan-3-ols are the main source of flavonoids in Western diets. They are characteristic compounds of tea, cocoa, wine, apple, pears, etc. In plant-based foods, they occur as simple monomers or as oligomers and polymers of up to 50 units (also known as proanthocyanidins or condensed tannins). When ingested, both monomeric and high molecular weight flavan-3-ols are poorly absorbed and metabolized in the first gastrointestinal tract, reaching the colon and becoming a suitable substrate for the local microbiota. These compounds undergo an extensive microbial metabolism leading to the formation of hydroxyphenyl-γ- valerolactones (PVLs), which are then absorbed by colonocytes before reaching the liver and being converted into phase II conjugated metabolites. Since the microbiota composition varies among individuals, it results in differences in the production of PVLs and, consequently, the health effects of flavan-3-ols might change at an individual level.

Another factor of variability might be due to a different asset in the fermentation of indigestible dietary carbohydrates, which are known to modify colonic pH through the production of short-chain fatty acids and may result in different profiles of gas production (i.e. hydrogen and methane), possibly affecting the bioconversion of flavan-3-ols as well. Nevertheless, these multiple variabilities are poorly understood to date.

Conditions

• Diet Modification

Interventions

DIETARY_SUPPLEMENT

Inulin

Powder of inulin fractions dissolved into 250 ml of water

DIETARY_SUPPLEMENT

green tea extract

Powder of green tea extract dissolved into 200 ml of water

DIETARY_SUPPLEMENT

grape seed

Powder of grape seed extract (rich in di-hydroxylated flavan-3-ol monomers) dissolved into 200 ml of water

DIETARY_SUPPLEMENT

grape seed extract

Powder of grape seed extract (rich in di-hydroxylated flavan-3-ol oligomers) dissolved into 200 ml of water

Sponsors & Collaborators

• Azienda Ospedaliero-Universitaria di Parma

  collaborator OTHER

• University of Parma

  lead OTHER

Principal Investigators

• Furio FB Brighenti, Professor · University of Parma

• Daniele DR Del Rio, Professor · University of Parma

• Pedro Miguel PM Mena Parreño, Ph.D. · University of Parma

• Rossella RD Dodi, M. Sc. · University of Parma

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

70 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2019-09-02

Primary Completion

2022-02-28

Completion

2022-12-27

Countries

• Italy

Study Locations